Improvement in screw-propellers



n. K. STEVENS & s. 'm LLEB.

' Screw Propellers.

P atented Sept'ember16,1873.

UNITED STATES. PAT NT "OFFICE ENEY K. STEVENS AND SOLOMON MILLER, 0FWATERLOO, NEW YORK;

SAID MILLER ASSIGNOR To SAID STEVENS.

lMPROlIEMENT m SCREW-PROPE'LLE'RS.

Specification forming part of Letters Patent No. 142,820, datedSeptember 16, 1873 application filed March 13, 1873 which we denominatethe Hercules Propel-V ler, of which the following is a specification:The first part of our invention consists in the construction of theblades of the propeller,

; by which, with a greater number of blades than is now used we have alarger and freer water space for the passage of the water through thewheel than any propeller heretofore oonstructedwith which we areacquainted, thereby furnishing a larger amount of water for thepropelling surfaces to act upon, by which the Slip is decreased when thewheel is in rapid motion.

The second part of our invention is the coupling for uniting thedriving-shaft with the propeller.

The construction of the propeller is as follows, referringto theaccompanying drawing, in which- Figure 1 is a general View of thepropeller. Fig. 2 is a side elevation. Fig. 3, the coupling joint.

.The hub a is of ordinary form tapered at each end. "The blades b. aresix in number, and are joined to the hub at an angle of aboutthirty-five degrees to the shaft. The center line of the blade b iscurved backward. It starts at an angle from a radial line at that point,curving upward at right angles to the line of the base, inclinedbackward to the center of the length of the blade; and thence curvingforward to the outer periphery of the blade, as clearly seen in thedrawing. The rear edge of the blade has a nearly similarcurve, roundingofi' at the periphery. front edge of the blade curves much more,extending forward of a radial line, and expandin g out the outercircumference of the blade to about double the breadth at the hub, andterminating forward in a rounded point, as clearly illustrated inFig. 1. Both faces of the blade are convex in their cross-section,tapering to an edge in front and rear, the thickness also diminishingfrom the hub to thetip.

The form we thus give to our propellerblades allows much greater spacefor water motion. This action of our propeller decreases.

the wash on the sides.

I The axis of our propeller is hung in bearings in a stout metalrudder-frame, c, having fenderbraces 01 projecting horizontallytherefrom, which surround the propeller. This rudder-frame is pivoted tothe sternpost of the boat, or to Outriggers e, and is so connected withthe tiller f above as 'to be readily swung to the right or left thereby.

The driving-shaft h of the engine projects out through the stern-post ofthe vessel, and is coupled with the axis of the propeller by a flexiblecoupling-joint, constructed so as to give freedom of motion, and at thesame time sufficient strength for the purpose. To effect this I form twojaws upon the shaft h, circular on their face 'i, as seen in thedrawing. Similar jaws are aflixed to the axis of the propeller, whichcouple into those on the shaft h. These jaws are united by joint-pins tohold them in place, thewhole strain coining upon the jaws. Having thusfully described our invention, what we claim, and desire to secure byLetters Patent, is-

' 1. The propeller constructed and arranged as herein described, havingthe blades formed I and aflixed to the hub, as herein specifically setforth in the above description, and for the purposes Specified.

2. The joint herein described, for coupling the propeller, withthedriving-shaft composed of strong jaws united together and held in placeby pins, as herein described.

In testimony whereof we hereto set our hands. HENRY K. STEVENS. SOLOMONMILLER.

In presence of- HUGH MONTGOMERY, H. VAN AMBURGH.

